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High-speed atomic force microscopy reveals a three-state elevator mechanism in the citrate transporter CitS
The secondary active transporter CitS shuttles citrate across the cytoplasmic membrane of gram-negative bacteria by coupling substrate translocation to the transport of two Na(+) ions. Static crystal structures suggest an elevator type of transport mechanism with two states: up and down. However, no...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
National Academy of Sciences
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8833178/ https://www.ncbi.nlm.nih.gov/pubmed/35101979 http://dx.doi.org/10.1073/pnas.2113927119 |
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author | Maity, Sourav Trinco, Gianluca Buzón, Pedro Anshari, Zaid R. Kodera, Noriyuki Ngo, Kien Xuan Ando, Toshio Slotboom, Dirk J. Roos, Wouter H. |
author_facet | Maity, Sourav Trinco, Gianluca Buzón, Pedro Anshari, Zaid R. Kodera, Noriyuki Ngo, Kien Xuan Ando, Toshio Slotboom, Dirk J. Roos, Wouter H. |
author_sort | Maity, Sourav |
collection | PubMed |
description | The secondary active transporter CitS shuttles citrate across the cytoplasmic membrane of gram-negative bacteria by coupling substrate translocation to the transport of two Na(+) ions. Static crystal structures suggest an elevator type of transport mechanism with two states: up and down. However, no dynamic measurements have been performed to substantiate this assumption. Here, we use high-speed atomic force microscopy for real-time visualization of the transport cycle at the level of single transporters. Unexpectedly, instead of a bimodal height distribution for the up and down states, the experiments reveal movements between three distinguishable states, with protrusions of ∼0.5 nm, ∼1.0 nm, and ∼1.6 nm above the membrane, respectively. Furthermore, the real-time measurements show that the individual protomers of the CitS dimer move up and down independently. A three-state elevator model of independently operating protomers resembles the mechanism proposed for the aspartate transporter Glt(Ph). Since CitS and Glt(Ph) are structurally unrelated, we conclude that the three-state elevators have evolved independently. |
format | Online Article Text |
id | pubmed-8833178 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | National Academy of Sciences |
record_format | MEDLINE/PubMed |
spelling | pubmed-88331782022-07-31 High-speed atomic force microscopy reveals a three-state elevator mechanism in the citrate transporter CitS Maity, Sourav Trinco, Gianluca Buzón, Pedro Anshari, Zaid R. Kodera, Noriyuki Ngo, Kien Xuan Ando, Toshio Slotboom, Dirk J. Roos, Wouter H. Proc Natl Acad Sci U S A Biological Sciences The secondary active transporter CitS shuttles citrate across the cytoplasmic membrane of gram-negative bacteria by coupling substrate translocation to the transport of two Na(+) ions. Static crystal structures suggest an elevator type of transport mechanism with two states: up and down. However, no dynamic measurements have been performed to substantiate this assumption. Here, we use high-speed atomic force microscopy for real-time visualization of the transport cycle at the level of single transporters. Unexpectedly, instead of a bimodal height distribution for the up and down states, the experiments reveal movements between three distinguishable states, with protrusions of ∼0.5 nm, ∼1.0 nm, and ∼1.6 nm above the membrane, respectively. Furthermore, the real-time measurements show that the individual protomers of the CitS dimer move up and down independently. A three-state elevator model of independently operating protomers resembles the mechanism proposed for the aspartate transporter Glt(Ph). Since CitS and Glt(Ph) are structurally unrelated, we conclude that the three-state elevators have evolved independently. National Academy of Sciences 2022-01-31 2022-02-08 /pmc/articles/PMC8833178/ /pubmed/35101979 http://dx.doi.org/10.1073/pnas.2113927119 Text en Copyright © 2022 the Author(s). Published by PNAS. https://creativecommons.org/licenses/by-nc-nd/4.0/This article is distributed under Creative Commons Attribution-NonCommercial-NoDerivatives License 4.0 (CC BY-NC-ND) (https://creativecommons.org/licenses/by-nc-nd/4.0/) . |
spellingShingle | Biological Sciences Maity, Sourav Trinco, Gianluca Buzón, Pedro Anshari, Zaid R. Kodera, Noriyuki Ngo, Kien Xuan Ando, Toshio Slotboom, Dirk J. Roos, Wouter H. High-speed atomic force microscopy reveals a three-state elevator mechanism in the citrate transporter CitS |
title | High-speed atomic force microscopy reveals a three-state elevator mechanism in the citrate transporter CitS |
title_full | High-speed atomic force microscopy reveals a three-state elevator mechanism in the citrate transporter CitS |
title_fullStr | High-speed atomic force microscopy reveals a three-state elevator mechanism in the citrate transporter CitS |
title_full_unstemmed | High-speed atomic force microscopy reveals a three-state elevator mechanism in the citrate transporter CitS |
title_short | High-speed atomic force microscopy reveals a three-state elevator mechanism in the citrate transporter CitS |
title_sort | high-speed atomic force microscopy reveals a three-state elevator mechanism in the citrate transporter cits |
topic | Biological Sciences |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8833178/ https://www.ncbi.nlm.nih.gov/pubmed/35101979 http://dx.doi.org/10.1073/pnas.2113927119 |
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